A: An EUA permits rapid response during a health crisis, such as the COVID-19 pandemic. An EUA allows the FDA to approve medical products to diagnose, treat or prevent life-threatening conditions when no approved alternative is available. FDA scientists review safety, effectiveness, quality control and manufacturing data to confirm that known benefits outweigh potential risks.

Additional data and clinical trial results are needed before the FDA fully approves a vaccine. Researchers continue to study safety and efficacy data in additional populations, such as in young children. Researchers also will track long-term safety and efficacy after vaccination.